In an effort to reduce back pain through early intervention techniques, some investigators have focused upon intraosseous nerves (“IONs”) contained within the vertebral bodies which are adjacent the problematic disc, and the basivertebral nerve (“BVN”) in particular.
For example, PCT Patent Publication No. WO 01/0157655 (“Heggeness”) discloses ablating nerves contained within the vertebral body by first boring into the vertebral body with a probe, placing the tip of the probe in close proximity to the nerve, and then ablating the nerves with the tip. Heggeness discloses using laser devices, electricity transmitting devices, fluid transmitting devices and thermal devices, and devices for carrying either chemotherapeutic or radioactive substances as candidate probes. Heggeness further discloses multiple methods of accessing the ION. However, each of these methods essentially disclose either i) boring a straight channel into the vertebra such that placement of an electrode tip near the end of that channel will bring the electrode tip sufficiently close to the ION to effect its ablation, or ii) accessing the BVN via the vertebral foramen. None of these techniques disclose a mechanical means for advancing the probe.
EPO Patent Published Patent Application No. EP 1 059067 A1 (“Cosman”) discloses ablative treatment of metastatic bone tumors, including those within the spine. Pain relief is reportedly achieved by penetrating the bone wall with a suitable probe, and applying heat through the probe to ablate either the bone tumor or the tissue near the bone tumor. Cosman also teaches that the treatment may also be used to ablate the nerves and nerve ramifications in and/or around the bone to desensitize them against further tumor encroachment. See Cosman at col. 11, lines 7-11. Cosman discloses probe devices whose electrodes can deviate from the axis of the access channel. In particular, Cosman discloses steerable tips, spring-like electrodes that take a straight shape within the catheter and then curve upon exiting the catheter. Cosman discloses that the curved portion of the electrode may be a rigid and rugged permanent curve, or it may be a flexible configuration so that it can be steered, pushed or guided by the clinician to be positioned at various location. See Cosman at 8,40-50. Again, none of these techniques disclose a mechanical means for advancing the probe.
In percutaneous procedures, (such as those described by Heggeness), imaging techniques (such as fluoroscopy) is typically employed by the clinician in order to accurately place the probe tip at the desired location. However, since exposure to radiation (such as X-rays) should be minimized, the clinician typically uses the fluoroscope only on an intermittent basis during a procedure, but not as a direct visualization aid in positioning the probe. That is, the clinician may place his or her hands in the fluoro field and move the probe “in the dark”, move out of the imaging field, activate the imaging device, check the probe location under active imaging, inactive the imaging device, place his or her hands in the radiation field and move the probe “in the dark”, etc. The failure to move the probe under direct imaging guidance may result in imprecise positioning of the probe, as the clinician's subjective feel plays a large role in estimating how a probe has been moved in the dark.
Moreover, since conventional RF probe heats only about a 1 cc volume in bone, the amount of imprecision associated with placing probes in the dark may affect the clinician's ability to locate a probe sufficiently close to a nerve in order to therapeutically treat the nerve.
Therefore, it is one object of the present invention to provide an apparatus that provides the clinician with more control over probe placement and location in electrode-related percutaneous procedures.
U.S. Pat. No. 6,280,441 (“Ryan”) discloses an RF electrode ablation probe having a housing and a semirigid, helical probe extending distally from the housing and having a sharpened distal tip. The probe advances into the patient by rotation relative to the housing, thereby twisting into the patient.
Ryan does not disclose a system wherein the distal tip of the probe is sufficiently sharp to pierce bone, wherein the probe can advance distally relative to its housing, wherein the distal portion of the probe is adapted to pass through the housing, nor wherein the outer surface of the probe has teeth adapted for ratcheting.
U.S. Pat. No. 6,210,415 (Bester) discloses a surgical drill guide having a guide tube advancable distally by a ratchet and pawl mechanism, wherein the distal end of the guide tube has a pair of pins. However, Bester does not disclose an apparatus having an electrode.
U.S. Pat. No. 6,016,452 (“Kasevich”) discloses an RF electrode system for use in the prostate, wherein actuating members 58,60 are mounted for reciprocal longitudinal movement relative to housing 52 to selectively move a plurality of electrodes between nondeployed position (in which the distal end of the electrode is within the housing) and a fully deployed position (in which the distal end of the electrode extends from the housing) (5,44-46). In one embodiment, longitudinal movement of actuating members 58,60 causes corresponding conjunctive movement of electrodes 72a-c. 
Kasevich does not disclose a system wherein the probe has a tip sufficiently sharpened to pierce bone. There is no provision for incremental distal advance of the electrode within the housing—simply actuation between one deployed and one nondeployed position. Kasevich does not disclose a system wherein the housing is adapted to allow the distal end of the probe to fully pass through the housing. Kasevich does not disclose a probe having an outside surface having teeth adapted for ratcheting.
U.S. Pat. No. 6,030,402 (Thompson) discloses an instrument for penetration of tissue including a penetration member and a distal backstop for limiting the penetration depth of the penetration member. Thompson further discloses advancing the penetration member and a distal backstop by a ratchet and pawl mechanism.
However, Thompson does not disclose an instrument having an electrode.
U.S. Pat. No. 6,231,571 (“Ellman”) discloses a probe having an electrode connected to a pull wire to allow the distal end of the probe to change direction. However, Ellman does not disclose an apparatus in which the probe may be distally advance relative to the housing.
U.S. Pat. No. 6,190,383 (“Schmaltz”) discloses an apparatus for thermal treatment of tissue comprising a plurality of electrodes that are rotatable about an elongated housing. The preferred tissue site is a myoma. The electrodes may include an external threaded portion 72 dimensioned to facilitate advancement and retention of the electrode in the tissue. Each electrode further possesses a sharpened distal end to facilitate penetration through tissue. Activation of a motor causes rotation of the drive shaft and advancement of the needle electrodes within the myoma. An axial force may be applied by the surgeon to the apparatus to facilitate insertion within the tissue.
U.S. Pat. No. 5,693,052 (“Weaver”) discloses an electrosurgical instrument for use in bipolar electrosurgery, including a probe having a nickel-free high chromium coating.
However, neither Ellman, Schmaltz nor Weaver disclose an apparatus in which the probe may be distally advanced relative to a housing.
In sum, the prior art does not appear to disclose a device designed to penetrate bone, is incrementally distally advanceable through the bone, and can therapeutically treat the bone.